Julia Roberts’ half-sister, who battled obesity and suffered cruel rejection by the “Pretty Woman” star, was found dead of an apparent suicide in her Los Angeles home, officials said Monday.

Bottles of prescription pills surrounded the body of Nancy Motes, 37, as she lay lifeless in the bathtub where her horrified fiancé discovered her Sunday.

“It was reported as a potential suicide,” Los Angeles County Coroner’s Assistant Chief Ed Winter told The Post. “But we’ll have to wait for tests to . . . know for sure.”

Motes struggled with weight her entire life, and even underwent gastric bypass surgery as she hit 300 pounds in 2010.

She said her decision to have the operation — which led to a dramatic weight loss — came after years of criticism by her sex-symbol sibling.

“When I was in high school and she was an adult, she would just let me know that I was ‘definitely overweight,’ ” she told the British newspaper The Sun. “She would make it quite clear to me — and in a not-so-nice manner.”

Motes, using the name @Dabbs76, also lashed out at Roberts on Twitter in the weeks before her death.

“So my ‘sister’ said that with all her friends & fans she doesn’t need any more love. Just so you all know ‘America’s Sweetheart’ is a B—H,” she snarled on Jan. 19.

“Do you want to be a fan of someone so cruel? She’s not even that good of an actress. Happy you totally F—ed with me?” she tweeted the same day.

The troubled Motes admitted her messages were rough, but could not contain her rage.

“I must admit I maybe going to [sic] far… But I never been so angry in my life. I’m actually a pretty easygoing, peaceful person,” she wrote.

Motes, whose other siblings are actor Eric Roberts and actress Lisa Roberts Gillan, said she always felt like a black sheep.

“When you’re in a family of very, very exceptionally beautiful people, it’s intimidating,” she told the paper. “I think that growing up as Pretty Woman’s little sister has definitely made me try to see the person inside and not the person outside.”

Motes once harbored her own Tinseltown dreams. After finishing school in 1995, she moved to LA, but her Oscar-winning sister, who has a different dad, was not supportive, she said.

“Julia did not want to see me go down that path, mostly because I was overweight,” Motes said.

Motes eventually gave up. She was set to marry John Dilbeck, who found her in the tub at about 2 p.m. Sunday, in May.

Although officials yesterday were eyeing suicide as the cause of death, Motes’ family released a statement to People magazine describing the death as a “drug overdose.”

“There is no official report from the coroner’s office yet,” the statement said. “The family is both shocked and devastated.”

Motes was to marry Dilbeck in May. She didn’t know if Julia would attend the wedding.

“It’s a work in progress, it’s not going to be fixed overnight,” she said of her relationship with Julia.